Pieces of wood of all kinds moving through wood processing machinery need to be carried at a controlled speed and to follow a well defined path to be properly processed. There is known in the art to provide conveying systems with a motorised pressing roll mounted on a pivoting frame. The press roll both moves the wood along its path and applies a pressure thereon to keep it on track. The pivoting movement of the frame is resiliently controlled, for example, through a pneumatic or a hydraulic jack. In these systems a lot of strain is imposed on the jack since its movement has to compensate for the unevenness of the wood surface and keep the pressure thereon constant. The jack often fails to react quickly enough to the bigger bumps on the wood's surface, temporarily loosing its grip on the piece of wood which may then deviate from the right path.